Attwood hull-mounted vents are designed to install by fastening as a complete unit from either inside or outside the hull. Ventilation hose (not included) twists into the bottom of the box to form a raised water barrier. Plastic vents are corrosion-resistant, will not discolor. All collector boxes and vents are designed for intake or exhaust and meet ABYC H-2 cross sectional area requirements. For use with Venturi, Flush Louvered or Trimline vents. Corrosion-resistant plastic. > For one 4" I.D. hose > Hole Size: 2-1/8" x 15-5/8" > Depth: 5" > For use with Attwood Vents BC-3764 (1494, 1423, 1424, 1496A)
